This invention relates generally to die cutting machines for making carton blanks, and in particular, to stiffening rail supports for interconnecting a stiffening rail to a frame assembly for a lower blanking tool that supports carton scrap during a blanking operation in a die cutting machine.
In the manufacture of cartons, small sheets of paper material having specific profiles are cut out of larger sheets of paper material. These smaller sheets are known as carton blanks that, in turn, are formed into cartons and/or boxes. The blanks are formed during a process known as a blanking operation in a die cutting machine.
In a die cutting machine, the blanks are cut, but not removed from a large sheet of paper material. After the blanks have been cut, the sheet is moved downstream in the die cutting machine to a blanking station where the sheet is positioned over a frame assembly for support. The frame assembly includes an outer frame and an inner grid having large openings that correspond in size, in shape and in position to the profile of the carton blank previously cut. Below the frame is a mechanism for stacking the carton blanks.
At the blanking station, an upper tool is used in combination with the lower tool or frame assembly to knock the carton blanks from the sheet of paper material while holding the scrap material that surrounds the blanks. The upper tool has a support board that moves vertically up and down in the die cutting machine, and the support board typically has a plurality of stand-offs depending therefrom that hold pushers spaced beneath the board which in turn are used to push the carton blanks from the sheet through the lower tool or frame assembly. A plurality of presser assemblies are also mounted in the support board and depend therefrom to hold the scrap material against the lower tool or frame assembly during the blanking operation so that the blanks may be pushed from the sheet. A presser assembly typically includes a presser rail which is biased downwardly away from the support board by a spring so that the rail is positioned slightly below the pushers. As the upper tool is lowered, the presser rail engages the sheet of paper material first such that a scrap portion of the large sheet of material is secured between the presser rail and the frame. The upper tool then continues to be lowered such that the sheet of material engages the inner grid within the frame while at substantially the same time the pushers engage the carton blanks and knock the blanks out of the sheet of material and through the inner grid. The carton blanks then fall into a stacking mechanism below the frame where the blanks are stacked for further processing.
The lower tool used in the blanking operation is typically comprised of a steel or aluminum outer frame that supports an inner grid. The inner grid is typically comprised of a plurality of lengthwise and crosswise extending bars. In order to secure the inner grid in place on the outer frame, the ends of each bar are typically screwed onto attachment pieces which, in turn, are mounted on the lengthwise and crosswise rails of the outer frame. Since the frame and grid support a sheet of paper material during the blanking operation, the grid must be configured to match or conform to the die cut in the sheet of paper material. In addition, the grid must be reconfigured whenever a different carton blank needs to be produced. Thus, unscrewing the inner grid from the outer frame oftentimes becomes very cumbersome and time consuming.
Therefore, it is a primary object and feature of the present invention to provide an improved stiffening rail support for interconnecting a stiffening rail to a frame assembly for a lower blanking tool of a carton die cutting machine to reduce flexing of the frame assembly during a blanking operation.
It is a further object and feature of the present invention to provide a stiffening rail support for interconnecting a stiffening rail to a frame assembly for a lower blanking tool that allows for the stiffening rail to be easily attached and removed from the frame asssembly.
It is a still further object and feature of the invention to provide a stiffening rail support for interconnecting a stiffening rail to a frame assembly for a lower blanking tool which is compatible with standard blanking operation machinery and which is relatively inexpensive.
In accordance with the present invention, a stiffening rail support is provided for attaching a stiffening rail to the outer frame for a lower blanking tool of a carton die cutting machine to discourage the flexing thereof. The stiffening rail support includes a clamp piece defining a vertically extending inner face, an opposite vertically extending outer face, and a bore extending between the inner face and the outer face along an axis at an acute angle to the outer face. A jaw element is operatively connected to the clamp piece so as to define a clamp cavity therebetween. The jaw element is movable between a clamping position for retaining a portion of the stiffening rail in the clamping cavity and a release position.
The jaw element includes a first clamping surface engageable with the stiffening rail when the jaw element is in the clamping position. The jaw element includes a second clamping surface that is engageable with the clamping piece when the jaw element is in the clamping position. The first and second clamping surfaces of the jaw element are generally arcuate and include apexes.
The stiffening rail support may also include a screw member for moving the jaw element between the clamping position and the release position. In addition, the acute angle of the bore between the inner and outer face is in the range of 30 degrees and 80 degrees. Preferably, the acute angle is approximately 65 degrees. It is contemplated to provide a lip in the outer face of the clamp piece. The lip is engageable with a corresponding ledge along the outer frame to support the clamp piece thereon. A fastening element extends through the bore in the clamp piece and is receivable in a corresponding slot in the outer frame to interconnect the clamp piece to the outer frame. A recess slot may be provided in the inner face of the clamp member to slidably receive a jogger disposed therein.
In accordance with a further aspect of the present invention, a stiffening rail support is provided for attaching a stiffening rail to the outer frame for a lower blanking tool of a carton die cutting machine to discourage the flexing thereof. A plate member defines inner and outer faces and a bore extending between the inner and outer face along an axis at an acute angle to the outer face. A clamping structure is operatively connected to the plate member and is movable between a clamping position for rigidly retaining a portion of the stiffening rail against the plate member and a release position.
The inner face of the plate member defines a recessed slot therein for slidably receiving a jogger. The clamping structure includes a jaw element having a first clamping surface engageable with the stiffening rail when the clamping structure is in the clamping position and a second clamping surface engageable with the plate member when the clamping structure is in the clamping position. The first and second clamping surfaces of the jaw element are generally arcuate and include apexes. A screw member moves the clamping structure between the clamping and the release positions.
It is contemplated that the bore extend between the inner and outer face at an angle in the range of 30 degrees and 80 degrees. Preferably, the angle of the bore is approximately 65 degrees. It is further contemplated to provide the outer face of the plate member with a lip. The lip is engageable with a corresponding ledge along the outer frame to support the plate member thereon.
In accordance with a further aspect of the present invention, a frame assembly is provided for a lower blanking tool of a carton die cutting machine. The frame assembly includes a rigid outer frame having a slot therein. A stiffening rail overlaps at least a portion of the outer frame. A stiffening rail support interconnects the stiffening rail to the outer frame. The stiffening rail support includes a plate member defining an inner face, outer face and a bore extending between an inner face and an outer face along an axis at an acute angle of the outer face. A clamping structure is operatively connected to the plate member and is movable between a clamping position for rigidly retaining a portion of the stiffening rail against the plate member and a release position. A fastening element extends through the bore in the plate member and is receivable in the slot in the outer frame to interconnect the plate member to the outer frame.
The acute angle of the bore extending through the plate member is in the range of 30 degrees and 80 degrees, and preferably, is approximately 65 degrees. The inner face of the plate member defines a recessed slot therein wherein a jogger may be slidably disposed. The clamping structure includes a jaw element having a first clamping surfaces engageable with the stiffening rail when the clamping structure is in the clamping position and a second clamping surface engageable with the plate member when the clamping structure is in the clamping position. The first and second clamping surfaces of the jaw element are generally arcuate and include apexes.